She passed emissions. I would theorize that even though it was not getting fuel to that area of the intake, it would still steal fuel from the other 3 injectors and result in the 3 that were firing getting a too-lean mixture which would cause excessive combustion temperatures and thus excessive NxOx. The intake is, after all, shared.

Moral of the story - pay attention to what that OBDII thingie is sayin'...